Minimally invasive methods for implanting a sacral stimulation lead

ABSTRACT

Methods and apparatus for implanting a neural stimulation lead in a patient&#39;s body are described. A lead assembly comprises a pointed-tip stylet, a stimulation lead, and an optional tube to deploy a fixation element attached to the lead. One embodiment of the implant methods starts with inserting the pointed-tip lead assembly directly into tissue. After the desired implant position is determined, the pointed-tip component is separated from the stimulation lead and removed from the tissue, leaving the stimulation lead implanted. After confirmation that the stimulation lead is in the right, tissue location, the pointed-tip component is removed from the body, leaving the stimulation lead in place. The stimulation lead can be connected to a neurostimulator to delivery therapies to treat neural disorders, such as urinary control disorders, fecal control disorders, sexual, dysfunction, and pelvic pain, etc.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No12/506,282, filed on Jul. 21, 2009, which claims priority from U.S.Provisional Application Ser. No. 61/082,271, filed Jul. 21, 2008.

TECHNICAL FIELD

The present invention relates to a neural stimulation lead assembly andminimally invasive implant methods associated with use of the describedlead assembly. More specifically, the present invention relates to alead assembly including a stimulation lead and a pointed-tip styletreceived in a lumen of the lead. Minimally invasive method involvesinserting the lead assembly into tissue without using a dilator.

BACKGROUND OF THE INVENTION

Many people suffer from an inability to control urinary function, i.e.,urinary incontinence. Different muscles, nerves, organs and conduitswithin the urinary tract cooperate to collect, store and release urine.A variety of disorders may compromise urinary tract performance andcontribute to incontinence. Many of the disorders may be associated withaging, injury or illness. For example, aging can often result inweakened sphincter muscles, which cause incontinence, or weakenedbladder muscles, which prevent complete emptying. Some patients also maysuffer from nerve disorders that prevent proper triggering and operationof the bladder or sphincter muscles.

Fecal incontinence is the inability to control bowel function. Fecalincontinence may be attributable to many physiological conditions, suchas damage to the muscles of the rectum (e.g., the anal internal orexternal sphincters), nerve damage, loss of storage capacity within therectum, and pelvic floor dysfunction.

Electrical stimulation of nerves may provide an effective therapy for avariety of disorders, including urinary incontinence and fecalincontinence. For example, an implantable neurostimulator can deliverelectrical stimulation to the sacral nerve to induce sphincterconstriction and thereby close or maintain closure of the urethra at thebladder neck. In addition, electrical stimulation of the bladder wallmay enhance pelvic floor muscle tone and assist fluid retention in thebladder or voiding fluid from the bladder.

In current clinical practice to minimally implant a sacral stimulationlead, the procedure starts with a kit comprising a needle and a dilatorthat are particularly adapted to enable introduction of aneurostimulation lead into a foramen to locate a distal leadelectrode(s) in operative relation to a sacral nerve. The needle isadapted to be inserted through an entry point of the skin or a skinincision posterior to the sacrum. The needle is guided along aninsertion path into a foramen to locate at least a distal portionthereof extending alongside a sacral nerve. A proximal portion of theneedle extends from the entry point away from the patient's skin. Thedilator is inserted over the needle proximal end and advanced distallyover the needle to dilate the insertion path to that of the dilatordiameter. The needle is then withdrawn through the dilator body lumen.The stimulation lead can now be advanced through the dilator body lumento locate the lead electrode into operative relation with the sacralnerve. The dilator is then withdrawn over or removed from thestimulation lead body.

The above practice requires multiple steps and disposable components ina kit to implant the stimulation lead. This takes time and creates extratrauma around the stimulation lead. Therefore, in the current invention,a simplified implant method, and a modified stimulation lead and kit aredescribed.

SUMMARY OF THE INVENTION

A minimally invasive implant method starts with inserting a pointed-tiplead assembly directly into tissue. The desired implant position isdetermined by electric stimulation either through the stimulation leador the pointed tip. Afterwards, the pointed-tip component is separatedfrom the stimulation lead and removed from the tissue, leaving thestimulation lead implanted. In one variation, a needle is first insertedto identify the optimal stimulation site. After marking the needle pathand position, the needle is removed and a pointed-tip stimulation leadassembly is inserted along the marked needle path. After confirmationthat the stimulation lead is in the right tissue location, thepointed-tip component of the lead assembly is removed from the body,leaving only the stimulation lead in place. This minimally invasiveimplant method can be practiced in a wide variety of neural stimulationapplications, including sacral nerve stimulation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of an implanted neurostimulator.

FIG. 2 shows a lengthwise cross-section view of stimulation leadassembly, with the proximal end of the pointed-stylet attached to thestimulation proximal end via a cap.

FIG. 2A is a cross-sectional view taken along line 2A-2A of FIG. 2

FIG. 2B is a cross-sectional view taken along line 2B-2B of FIG. 2A.

FIG. 3 shows the proximal end of the stylet uncoupled from stimulationlead of FIG. 2 by removing the cap.

FIG. 4 shows how a tube being pushed over the lead to extend fin-typefixation elements attached at the lead intermediate section.

FIG. 5 shows the stimulation lead in a deployed state after separatelyremoving the stylet and the tube used for activating the fixationelements on the lead body.

FIG. 6 shows a cross-section view of a stimulation lead assemblyinserted through tissue and into a foramen, led by the pointed-tipstylet at the distal end.

FIG. 7 shows the stylet retracted from the distal end of FIG. 6 andplacement of the stimulation lead at the stimulation site.

FIG. 8 shows a cross-section view of a tube being pushed over theimplant lead to activate the fixation element on the intermediateportion of the lead.

FIG. 9 is a cross-sectional view showing deployment of the fixationelement in tissue by the tube.

FIG. 10 shows a stimulation lead design with multiple fixation elementsattached at different locations along the lead intermediate section.

FIG. 11 shows a cross-section view taken along line 11-11 of FIG. 10.

FIG. 12 shows an activation tube used to deploy the fixation elementsshown in FIG. 10.

FIG. 13 shows a cross-sectional view along line 13-13 of FIG. 12.

FIG. 14 shows tapered coils as fixation elements along a stimulationlead.

FIG. 15 shows the implant of stimulation lead assembly and deployment oftapered coil fixation in tissue.

FIG. 16 shows a stimulation lead assembly having an elongatedpointed-tip lead carrier.

FIG. 17 shows a cross-sectional view of the lead assembly with thepointed-tip lead carrier disengaged from the lead.

FIG. 18 is a cross-sectional view taken along line 18-18 of FIG. 16.

FIG. 19 shows a cross-sectional view of the disengagement of leadcarrier from lead via rotation.

FIG. 20 shows a complete disengagement of the lead carrier from the leadafter being rotated out of the way.

FIG. 21 shows a cross-sectional view of the lead after implantation,with both the stylet and the lead carrier removed from the implant site.

FIG. 22 is a flowchart of a first minimally invasive method embodiment.

FIG. 23 is a flowchart of a second minimally invasive method embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an embodiment of an implanted neurostimulator 26 forstimulating sacral nerves 27 located near the sacrum 28. The sacralnerves are accessible through an entry point, in the skin along aninsertion path 33 into a foramen 31 to reach a desired location 35. Aneurostimulation system can include a stimulation lead 30, an optionallead extension 32, an implantable neurostimulator 26, a physicianprogrammer (not shown), and a patient programmer (not shown). Thestimulation lead 30 has electrical contacts 34 positioned on the distalend to stimulate nerves, and connectors (not shown) on the proximal endto connect to a lead extension or directly to the implantableneurostimulator 26.

The implantable neurostimulator 26 provides a programmable stimulationsignal that is delivered to a desired location to stimulate selectednerves. The implantable neurostimulator 26 is typically implanted in asubcutaneous pocket around the upper buttocks, sometime after thestimulation lead 30 has been implanted and its effectiveness verified.The physician programmer is used by the clinician to program thestimulation signal produced by the implantable neurostimulator 26. Thepatient programmer allows the patient to communicate with theimplantable neurostimulator to control certain parameters of thestimulation signal typically selected by a clinician. For example, witha pelvic floor disorder, a patient can typically control stimulationsignal parameters such as voltage amplitude.

As a preferred embodiment of the current invention, FIG. 2 shows a leadassembly 36 comprising a stimulation lead 37 and a pointed tip stylet60. The stimulation lead 37 has a proximal portion 38, a distal portion40 and an intermediate portion 39. As one of the preferred embodiments,the distal portion has four electrical contacts 44, 46, 48 and 50serving as stimulation electrodes. These contacts can be made ofiridium/platinum alloy rings. The lead proximal portion also has fourelectrical connectors 52, 54, 56 and 58 for connecting the lead proximalportion 38 to the neurostimulator 26. These electric connectors can bemade of stainless steel rings.

Electric pulses from the neurostimulator 26 run through the proximalconnectors 52, 54, 56 and 58 and along the lead body to the distalelectrodes 44, 46, 48 and 50 via respective electrical wires 61A, 61B,61C and 61D (FIG. 2A). For example, as shown in FIGS. 2, 2B and 3, thedistal electrode 44 is connected by wire 66D to the proximal connector52 and electrode 48 is connected by wire 66B to the proximal connector56. These wires are embedded in the lead insulation body 70 (FIG. 2A).The connection of a wire at its ends to a distal electrode and aproximal connector can be achieved by various means, for example, laserwelding. This is shown in FIG. 2A where a laser welded connection 68links wire 61A to electrode 50.

Typically the insulation portion of the lead body is made ofbiocompatible silicone or polyurethane. As shown in FIGS. 2 and 3, theproximal connectors 52, 54, 56 and 58 and distal electrodes 44, 46, 48and 50 can be partially embedded in the lead body to form a diametricprofile and to minimize trauma during lead implant. This partialembedding can be achieved by grinding or thermal reflow.

The lead body has a central lumen 41 extending from the proximal portion38 to the distal end 40. The stylet 60 runs through the central lumenthereof. The stylet 60 has a distal end 64 with a pointed tip 65. Inuse, the distal end 64 extends out of the lead body a sufficientdistance to expose the pointed tip 65. The stylet 60 also has a couplingelement 62 at its proximal portion 63 that couples with the leadproximal portion 38. As shown in FIG. 2, this coupling element 62 can bea removable cap attached at the stylet proximal end 63. As a variationin a preferred embodiment, this coupling element can also be removablyattached to the stylet proximal end 63 and lead proximal portion 38, forexample a clamp holding the lead and the stylet together.

During insertion of the lead assembly 36 into tissue, the couplingelement 62 helps prevent stylet movement inside the lumen 41. That is sothe lead assembly 36 can be inserted as a single unit by holding bothits intermediate portion 39 and optionally its proximal portion 38.

As shown in FIG. 3, after the lead 36 assembly is inserted into tissue,the coupling element 62 is removed and the stylet 60 moved back andforth within the central lumen 41 by pulling or pushing its proximal endagainst the lead proximal portion 38. The stlyet 60 can be made of metalthat is electrically conductive. That is so electric pulses can be fedfrom its proximal end into its distal end 64 where the pulses will evokea patient motor or sensory response. To enhance the accuracy andlocalization during the desired stimulation site probing process, thestylet distal end can be partially insulated, for example by a thinlayer of polytetrafluoroethylene (PTFE), with only the tip 65 being leftexposed. By moving the pointed-tip stylet freely inside the lead centrallumen 41, a desired stimulation location can be probed by the stylet 60,preferably aided by the patient motor or sensory response.

Once a desired stimulation location has been identified using the tip 65of the stylet 60, the lead 37 is positioned close to the desiredlocation by holding the intermediate portion 39 and pushing the leadforward over the stylet. To facilitate lead advancement through tissueover the stylet, FIG. 2B shows a tapered end 42 at the lead distalportion 40. The final location of the lead can be verified by feedingelectric pulses from at least one of the lead proximal connectors 52 to58 to at least one of the distal electrodes 44 to 50.

Once verification of the desired lead placement is complete, it isnecessary to anchor the lead, for example by a fixation element build onthe stimulation lead 37. This fixation element is deployed into tissuesurrounding the lead. Once deployed, the fixation element prevents leadmovement in both longitudinal and lateral directions.

As shown in FIGS. 2, 4 and 5, one preferred embodiment of a fixationelement, is of a fin-like structure 66. The fins 66 are finger-likestructures having an length substantially longer than their diameter orwidth taken along a cross-section perpendicular to the length thereof.They are preferably of an elastic material, for example, of polyurethaneor silicone and only one of their ends is attached on the outer surfaceof the lead intermediate portion 39. Attachment can be achieved byinjection molding or adhesive bonding. Before the fixation fins 66 aredeployed into tissue, the opposite ends of the fins should be pointedtoward the lead proximal portion 38. That is in order to reduceresistance when entering tissue during the lead insertion process. Afterthe desired stimulation location is identified and the fixation fins 66are ready to be deployed, a preferred embodiment of the currentinvention includes a tube 72 (FIG. 4). The tube 72 is positioned overthe lead body and pushed down from the proximal portion 38 toward thelead intermediate portion 39 until the distal tube end 74 touches thefixation fins 66. Tube 72 first touches the non-attached ends of thefins 66 and pushes them away from the lead intermediate portion 39. Thismovement stops when the tube 72 contacts the attached ends of the fins66. Thus, the fixation element is moved from its initial state (FIG. 2)into its final deployed state (FIG. 4) via tube 72. FIG. 5 shows thelead with the fixation fins 66 deployed and the tube 72 removed from thelead 37.

As a preferred embodiment of the current invention, FIGS. 6 to 9 show aminimally invasive method for implanting the above-described stimulationlead-stylet assembly 36 percutaneously. The method is also described inthe flowchart of FIG. 22.

Briefly, a local anesthetic is typically applied to the area where thestimulation lead-stylet assembly 36 will be implanted, for example,posterior to the sacrum 28. By using local anesthesia, an implantingclinician can include the patient's conscious sensory responses toelectric stimuli to aid in placing the stimulation lead-stylet assembly36.

The lead-stylet assembly 36 is hand guided 98 into the foramen 31 alongan insertion path 33. The foramen's 31 approximate location can be foundusing anatomical landmarks, fluoroscopy or x-ray images. Once thelead-stylet assembly 36 has been placed inside the foramen 31, thecoupling 62 between the stimulation lead and stylet is removed. Thedesired stimulation site can be first probed by the stylet and sensed bya variety of means such as by applying electric pulses to the stylet 60at its proximal end 63 to evoke a patient response, such as a motor orsensory response. As shown in FIG. 7, once the stylet is in place, thetapered stimulation lead can be pushed over the stylet and moved intothe identified stimulation site.

Before anchoring the lead with the fixation element 66 using the tube72, however, verification of lead placement at the desired locationshould he made. This is done by feeding electric pulses to at least oneof the lead proximal electric connectors 52, 54, 56 and 58, and sensingor stimulating by at least one of the lead distal electrodes 44 to 50.

FIGS. 8 and 9 show the step 100 of anchoring the lead 36. This is doneby pushing the tube 72 over the lead-stylet assembly 36 until, the tubecontacts the fixation element. 66. The force exerted by the tube distalend. 74 on the fixation fins 66 pushes their non-attached ends away fromthe surface of the lead intermediate portion 39 and into the tissue,preferably at a fascia layer, such as the lumbosacral fascia layer. Thelubosacral fascial layer may be located at different depth from the skinfor different patient. For that reason, the provision of multiplefixation fins enables the clinician to successfully deploy at least oneof them at the preferred lumbosacral, layer are described.

A preferred embodiment comprising multiple fixation fins supported on astimulation lead 37 is shown in FIG. 10. By way of example, thisembodiment has three fin-like fixation elements 66A, 665 and 66C, eachhaving only one end attached to the lead body. The opposite end of thefins extends away from the lead surface when it is deployed by tube 72in a similar manner as shown in FIG. 4. These fixation elements can bemade of material having elastic properties, such as polyurethane orsilicone, and are similar to the fins 66 described in FIGS. 2, 4 and 5.However, they are attached to the lead intermediate portion 39 atdifferent axial locations. Initially, the non-attached ends point to thelead proximal portion 38 during insertion of the lead-stylet assembly36. Once deployed into tissue, as shown in the cross-sectional view ofFIG. 11, the three fixation elements are preferably about 120 degreesfrom each other.

The deployment tube 72 shown in FIG. 12 has three slots 76, 78 and 80with different lengths measured from the tube 72 distal end at the tubedistal portion 74. As shown in FIG. 13, these slots are also about 120degrees apart from each other. That is so when the tube 72 is pushedover the lead-stylet assembly 36, the length and orientation of thevarious slots deploys only one of the fixation fins 66A to 66C. Forexample, slot 76 only deploys fixation element 66A, slot 78 only deploysa respective fixation element 66B, and slot 80 only deploys fixationelement 660.

FIG. 14 shows another preferred embodiment of a fixation structure. Inthis embodiment, there are three tapered coils 82A, 82B and 82C, eachhaving a smaller diameter end and a larger diameter end. Only thesmaller diameter end is attached to the surface of the lead intermediateportion 39 with the remainder of the coil surrounding the perimeter ofthe lead. The tapered coils can be twisted in one direction at theirlarger end. This causes their larger diameters to shrink so that thecoil fits into a tube 73 whose inner diameter is smaller than the coil'suncoiled diameter. The lead-stylet assembly in this case will alsoinclude the tube 73 covering only the lead intermediate portion 39 andpart of lead distal portion 38 (not shown).

During the implanting process shown in FIG. 15, the entire lead assemblyincluding the tube 73 is inserted into body tissue. After the desiredstimulation site has been identified by the pointed stylet 60 and thefixation elements 82A, 82B and 82C are ready to be deployed, the tube 73is retracted from the stimulation lead. As this movement takes place,the coils are released from inside the tube 73 and expand like a torsionspring surrounding the lead. At least one of the tapered coils ispreferably expanded within the lumbosacral fascial layer. These taperedcoils are preferably made of biocompatible metals, such as stainlesssteel, platinum, titanium, NP35N, or nitinol.

While the larger ends of the coils are shown facing distally, that isnot necessary. In an alternative embodiment, the larger coil ends canface proximally. Still further, one of the coils could have its largerend facing distally while another has its larger end facing proximally.

Referring back to the flowchart 92 shown in FIG. 22, after deployment ofthe fixation element into tissue, preferably in the lumbosacral fasciallayer, the point-tip stylet 60 is removed 102 via the lead central lumen41. To make sure there is no displacement of the stimulation lead duringdeployment of the fixation elements 66 and removal of the tube 72 ortube 73 and stylet 60, re-verification of lead position at the desiredstimulation site should be repeated as described previously. Afterwards,a skin incision is made for implanting the neurostimulator, i.e., theimplantable pulse generator (IPG). The lead proximal portion 38 istunneled under the skin to bring it adjacent to the implanted IPG andthen to the lead proximal connectors 52, 54, 56 and 58 are connected 106to the appropriate IPG receptacles (not shown). After the IPG isactivated, patient feedback is acquired to make sure the desired neuralstimulation is achieved. Finally, the skin incisions for both the leadentry point and the IPG implant site are closed 108.

FIG. 23 shows a variation 94 of the preferred embodiment in FIG. 22 ofthe current invention. Instead of inserting a whole lead-stylet assembly36, a needle similar to the stylet 60 and having a diameter much smallerthan the assembly 36 is inserted first 110 to probe the desiredstimulation site 112. Once the desired site is identified, the implantclinician records the needle depth and orientation as a reference, andthe needle is removed. The recorded needle depth and orientationinformation is then used to guide insertion 96 of lead-stylet assembly36. The remainder of the procedure steps are the same as in flowchart92. However, comparing the flowcharts 92 and 94, it is seen that thelatter enables an implant clinician to probe several sites withrelatively more ease before implanting the lead assembly 36 than in theformer. This helps reduce trauma to the patient and enhance therapyeffectiveness.

Another variation of the preferred embodiment of the lead-styletassembly 36 is the implant assembly shown in FIGS. 16 and 17 having anelongated carrier body 84, a lead body 37 and a stylet 88. The lead body37 has a central lumen 41, which does not run through to the lead tip.This means that the distal end of the stylet 88 within the lead body 37is not exposed out from the distal end of the lead tip 40. In thisembodiment, the carrier body 84 has a pointed tip 86 for cutting throughtissue during implantation. The side wall of the carrier body 84 issized to accommodate the lead body 37. With the lead body 37 nested inthe carrier body, the lead tip 40 resides in a longitudinal cavity 90extending along the distal end of the carrier.

The distal end of the carrier 84 is then inserted into tissue in asimilar manner as previously described with respect to the assembly 36.To disengage the carrier body $4 from the lead body 37, the clinicianholds the lead body 37 and stylet 88 in place and pushes the carrierbody 84 further forward, as shown by the arrow in FIG. 17. This causedthe lead distal end 40 to separate from the carrier body cavity 90. Toremove the carrier body 84 from the tissue, the carrier body 84 isrotated out of the way relative to the lead body 37 (FIG. 19). Thisensures that the cavity 90 does not re-engage with the lead tip 40during removal (FIG. 20). After the carrier body is removed, the lead isimplanted into body tissue using either the previously describedfixation fins 66 or the tapered coils. The stylet 88 is then removed,from the lead central lumen with only the stimulation lead 35 being leftin place (FIG. 21).

Thus, embodiments of minimally invasive sacral lead implantation methods92 and 94 are disclosed with many benefits. Embodiments of the methodscan simplify the implant procedure, reduce trauma to the patient duringimplant procedure, reduce patient recovery time, and reduce healthcarecosts. One skilled in the art will appreciate that the present inventioncan be practiced with embodiments other than those disclosed. Thedisclosed embodiments are presented for purposes of illustration and notlimitation, and the present invention is limited only by the claims thatfollow.

What is claimed is:
 1. A stimulation lead assembly, which comprises: a)a neural stimulation lead, comprising: i) an elongated, insulated leadbody having a length extending from a proximal lead portion to a distallead portion; ii) at least one stimulation electrode at the distal leadportion, at least one electrical connector at the proximal lead portion,and at least one conductor providing electrical continuity from theconnector to the electrode; iii) a hollow lumen extending along theentire length of the lead body from the proximal lead portion to thedistal lead portion; and iv) at least one fixation finger attached to anouter surface of the lead body, wherein the lead element is deployableto secure the lead in body tissue; and b) a removable elongated leadcarrier having a pointed-tip, wherein the carrier comprises a side wallwith a cavity therein for carrying the lead through body tissue to anintended implantation site in body tissue.
 2. The lead assembly of claim1 wherein the fixation finger has an attached end secured to the outersurface of the lead body and a free end movable from a first positionclosely spaced to the outer surface thereof to a second, deployedposition spaced from the lead body a greater distance than that of thefirst position.
 3. The lead assembly of claim 1 wherein the fixationfinger has a length that is significantly longer that either its widthor diameter taken along a cross-section perpendicular to the length. 4.The lead assembly of claim 2 further comprising a tube that is sized toslide over the outer surface of the lead body to contact the at leastone fixation finger to thereby move the finger from the first positioninto the second, deployed position.
 5. The lead assembly of claim 1wherein there are at least two fixation fingers, each having an endsecured to the outer surface of the lead body and a free end that ismovable from a first position closely spaced to the outer surfacethereof to a second, deployed position spaced from the lead body agreater distance than that of the first position and wherein a firstdistance from a distal end of the lead to where the attached end of afirst one of the fingers is secured to the lead body is substantiallydifferent than a second distance measured from the distal lead end towhere the attached end of the second one of the fingers is secured tothe lead body.
 6. The lead assembly of claim 5 further comprising a tubethat is sized to slide over the outer surface of the lead body tocontact the at least two fixation fingers and move them from the firstposition into the second, deployed position and wherein the tubeincludes at least two longitudinal slots of different depths thatcorrespond to the different distances that the two fixation fingersattached to the lead body are spaced from the distal lead end to therebysimultaneously deploy the fixation fingers at different distances fromthe distal lead end when the tube is slid over the outer surface of thelead body to contact the fixation fingers.
 7. The lead assembly of claim1 wherein there are three fixation fingers, each having their respectiveattachment ends secured to the lead body at significantly differentdistances measured from the distal lead end than the other two fixationfingers.
 8. The lead assembly of claim 1 wherein the lead body and theat least one fixation finger are of polymeric materials selected fromthe group consisting of silicone, polyurethane, and mixtures thereof. 9.The lead assembly of claim 1 wherein the lead body and the at least onefixation finger are of polymeric materials that are either the same ordifferent.
 10. The lead assembly of claim 1 as part of an assemblyincluding a pointed-tip stylet sized to be housed inside the lumenextending through the lead body.
 11. The lead assembly of claim 10wherein the stylet is longer than the lead body so that with a proximalend of the stylet detachably secured to a proximal end of the lead, adistal end of the stylet extends out past a distal end of the lead. 12.A stimulation lead assembly, which comprises: a) a neural stimulationlead, comprising: i) an elongated, insulated lead body having a lengthextending from a proximal lead portion to a distal lead portion; ii) atleast one stimulation electrode at the distal lead portion, at least oneelectrical connector at the proximal lead portion, and at least oneconductor providing electrical continuity from the connector to theelectrode; and iii) at least one fixation finger attached to an outersurface of the lead body, wherein the lead element is deployable tosecure the lead in body tissue; and b) a removable elongated leadcarrier having a pointed-tip, wherein the carrier comprises a side wallwith a cavity therein for carrying the lead through body tissue to anintended implantation site in body tissue.
 13. The lead assembly ofclaim 12 wherein the fixation finger has an attached end secured to theouter surface of the lead body and a free end movable from a firstposition closely spaced to the outer surface thereof to a second,deployed position spaced from the lead body a greater distance than thatof the first position.
 14. The lead assembly of claim 12 wherein thefixation finger has a length that is significantly longer that eitherits width or diameter taken along a cross-section perpendicular to thelength.
 15. The lead assembly of claim 12 further comprising a tube thatis sized to slide over the outer surface of the lead body to contact theat least one fixation finger to thereby move the finger from the firstposition into the second, deployed position.
 16. The lead assembly ofclaim 12 wherein there are at least two fixation fingers, each having anend secured to the outer surface of the lead body and a free end that ismovable from a first position closely spaced to the outer surfacethereof to a second, deployed position spaced from the lead body agreater distance than that of the first position and wherein a firstdistance from a distal end of the lead to where the attached end of afirst one of the fingers is secured to the lead body is substantiallydifferent than a second distance measured from the distal lead end towhere the attached end of the second one of the fingers is secured tothe lead body.
 17. The lead assembly of claim 16 further comprising atube that is sized to slide over the outer surface of the lead body tocontact the at least two fixation fingers and move them from the firstposition into the second, deployed position and wherein the tubeincludes at least two longitudinal slots of different depths thatcorrespond to the different distances that the two fixation fingersattached to the lead body are spaced from the distal lead end to therebysimultaneously deploy the fixation fingers at different distances fromthe distal lead end when the tube is slid over the outer surface of thelead body to contact the fixation fingers.
 18. The lead assembly ofclaim 12 wherein there are three fixation fingers, each having theirrespective attachment ends secured to the lead body at significantlydifferent distances measured from the distal lead end than the other twofixation fingers.
 19. The lead assembly of claim 12 wherein the leadbody and the at least one fixation finger are of polymeric materialsselected from the group consisting of silicone, polyurethane, andmixtures thereof.
 20. The lead assembly of claim 12 wherein the leadbody and the at least one fixation finger are of polymeric materialsthat are either the same or different.